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PEP 288: Generator Attributes

Bengt Richter bokr at oz.net
Wed Dec 4 01:22:20 EST 2002 
On 4 Dec 2002 00:08:39 GMT, bokr at oz.net (Bengt Richter) wrote:
[...]
>
>Note that a generator could now be also used with map, reduce, and filter as functions
>as well as sequence sources. E.g., IWT you could write compile as a string filter.
>
And also note that the function associated with the generator object could be
recursive, even involving other recursive functions recursively calling back!
This would be a consequence of changing yield to act according to its dynamic position in
execution. I.e., yield becomes like raising an exception without unwinding the stack, and
instead tracing it down to the first[1] generator __call__ frame.

[1] Hm... I wonder if a targeted yield that could find a particular generator __call__ frame
would be of use. You could specify an optional name in the call to the generator
factory method, which would default to the name of the function instance passed to it.
Then you could potentially suspend a context with one or more internal generators running.

This could be nice for coroutine multitasking, to yield back to a scheduler without having
to give up the state of active generators within tasks.

You'd need syntax to use it, e.g., maybe

    yield some_value as 'name_string' # re-using 'as'

e.g., alluding to foo function-result in "as foo" when returning to the generator __call__
context that made the primary call to foo.

Regards,
Bengt Richter
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